A typical wireless mobile communication network is made of a number of cells, each of which includes at least one fixed-location transceiver known as a cell site or base station. The base station within each cell provides radio coverage for a variable number of mobile communication devices located within the geographic service area the cell. Radio coverage for base stations in nearby cells may overlap so that a mobile communication device in any one cell can communicate through and transition into other cells as the user roams, including handoff during an ongoing communication. The base station is continuously broadcasting radio frequency signals in the cell to identify itself and receive signals from the mobile communications devices that are located within that cell. The base station communicates with the wireless mobile communication devices within the cell by receiving and transmitting RF signals. When a call is made from the mobile communications device, the call attempt signaling is transmitted by the mobile communication device to the base station with the strongest RF signal (typically the closest physical base station). The selected base station receives and initially processes the call.
In recent years, wireless mobile communications devices have increasingly been used by criminal and terrorist organizations during the commission of a crime or attack. For example, during a three-day terrorist attack that struck several locations in Mumbai, India during late 2008, the attackers used mobile communications devices to coordinate the attack, monitor international reaction to the attacks, and keep abreast of police and military efforts to end the attack. The attackers also used mobile communication devices to order the killing of hostages and to adjust other tactics while the attacks were underway.
Currently, there is a process between the National Communication Service (NCS) and wireless mobile communication network carriers, such as Verizon Wireless, to prevent mobile communication in an affected area. This process defines a procedure for shutting down mobile communications in a given number of cells within the affected area (i.e., affected cells) by shutting off all transmit amplifiers within the base stations in each cell so as to stop transmission of RF signal from the base station in the affected cell. However, given the nature of RF propagation, once a base station shuts down, the RF from base stations in the surrounding cells fills the affected cell. Although the performance may not be the same in the affected cell, the RF from the surrounding areas often would be sufficient for communications use.
Due to the nature of RF propagation, the current form of shutting down mobile communications in a given cell requires an excessively large number of base stations be shut down. This includes shutting down the base stations in the affected cells and also shutting down base stations in surrounding cells that would propagate RF into the affected cells. As an example, in the case of New York City, in order to shut down mobile communications in Mid-town Manhattan, it would be necessary to shut down base stations in all cells located in Mid-town Manhattan (i.e., the affected cells) and also shut down all base stations in cells in New York City's other four boroughs—Bronx, Brooklyn, Queens, and Staten Island—and in New Jersey several miles west of the Hudson River (i.e., the surrounding cells). By shutting down the mobile communications in both the affected and surrounding cells, the general public located in the surrounding cells is prevented from communicating on the mobile communications network. This resulting shut down of mobile communications in the surrounding cells leads to a loss of revenue in both the affected and surrounding cells, thereby complicating the decision to shut down the mobile communications network.
The current method also does not allow emergency service personnel in the affected and surrounding cells to communicate on the wireless mobile communication network. Such emergency service personnel include, for example, E911 personnel, Wireless Priority Service (“WPS”) personnel, or public safety personnel Further, because all mobile communications are shut down in the affected and surrounding cells, the general public is unable to communicate on the mobile communication network with emergency service agencies (such as E911) or emergency service personnel.
Hence a need exists for more effective techniques to selectively prevent mobile communication in affected cells without preventing mobile communications in cells surrounding the affected cells.